University of Oulu

Ramesh Babu, Shashank; Ivanov, Dmitry; Porter, David (2018) Influence of microsegregation on the onset of the martensitic transformation. ISIJ International

Influence of microsegregation on the onset of the martensitic transformation

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Author: Ramesh Babu, Shashank1,2; Ivanov, Dmitry3; Porter, David1
Organizations: 1Materials and Production Engineering, Faculty of Technology, University of Oulu, P.O. Box 4200, Oulu, 90014 Finland
2SSAB Europe Oy, Raahe, 92101 Finland
3EFD Induction a.s, Bøleveien 10, Skien, 3724 Norway
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2018110647366
Language: English
Published: Iron and Steel Institute of Japan, 2018
Publish Date: 2018-11-06
Description:

Abstract

Due to the volume change accompanying the fcc to bcc or bct crystal structures in steels, it is a common practice to determine phase transformation temperatures using dilatometry. The martensite start temperature (Ms) is often of particular interest. Experimentally, it is found that the start of the martensite transformation is not indicated by a sharp change in the slope of the dilatation curve as is predicted by the Koistinen – Marburger equation. Rather, there is a gradual change in the slope such that the martensite start temperature is ill-defined. The current work shows that this gradual change in slope can be related to chemical inhomogeneity in the steel caused by interdendritic microsegregation. It is shown that combining the Koistinen – Marburger equation with measured concentration profiles allows experimental dilatation curves to be well predicted.

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Series: ISIJ international
ISSN: 0915-1559
ISSN-E: 1347-5460
ISSN-L: 0915-1559
Volume: In press
Article number: ISIJINT-2018-424
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: The authors are grateful for financial support from the European Commission under grant number 675715 –MIMESIS – H2020-MSCA-ITN-2015, which is a part of the Marie Sklodowska-Curie Innovative Training Networks European Industrial Doctorate Programme.
EU Grant Number: (675715) MIMESIS - Mathematics and Materials Science for Steel Production and Manufacturing
Copyright information: © 2019 ISIJ. Published in this repository with the kind permission of the publisher.